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Template:Episode Quote "You Don't Know Jack" is the twentieth episode of Season 4 of Grimm and the eighty-sixth episode overall. It first aired on May 1, 2015 on NBC.


Nick, Hank, Monroe, and Wu arrive at the burned trailer ("Iron Hans") and go inside where they find mostly everything burned. Nick opens the weapons cabinet and finds many weapons survived the fire. Monroe grabs the Siegbarste Gewehr out of the cabinet and is relieved to find that it is still in good condition. Wu finds a diary on the ground that is partially burned, but overall is okay. Monroe then suggests they take what's left to the spice shop.

Juliette arrives at her and Nick's house and writes an email to Kelly that says Nick is in trouble and he may be killed if she doesn't come. Juliette makes note that the house is safe and sends the message.

Nick, Hank, Monroe, and Wu work on getting items out of the trailer and Wu asks Nick if he is going to go after Juliette, and he asks "What do you think?"

Juliette gets a response from Kelly saying that she is on her way. Juliette then deletes the evidence.

Elsewhere in Portland, two prostitutes, Heidi McDunnah and Mary Ann Casey are on a street corner waiting for their next clients. Mary Ann compliments Heidi's new hair and says it's too cold. She woges and says it's much warmer now. A car pulls up and Mary Ann tells Heidi she can take this one. Soon after Heidi leaves, a man walks up to Mary Ann and she asks him what he is looking for. He tells her "Something a Kehrseite couldn't handle, what you really are." Mary Ann woges and asks him if he means something like this. He tells her now she is beautiful and she asks him if he has a special place to go. He tells her he has a "lovely spot" and they leave. They arrive to a big open area and the man says he thinks they should do it right there. Mary Ann doesn't like the idea of doing it on the ground and starts to leave, but the man grabs her arm, pulls her back, and slits her throat.

In the spice shop, Rosalee and Adalind work on the suppressant and Rosalee asks how the suppressant should work and Adalind tells her she doesn't know how it works, she just knows it should work. Rosalee gets a little upset about Adalind saying the suppressant "should" work in stead of being more sure. She tells Rosalee she doesn't do this kind of thing all the time and then tells her she was perfectly happy until Nick's aunt came to town. Adalind realizes it doesn't matter what she says since everyone hates her anyway. Adalind tells Rosalee that she trusted her when she was staying with her and Monroe ("The Law of Sacrifice") ("Nobody Knows the Trubel I've Seen") and she thought she was trying to help her. Rosalee tells her she doesn't feel good about what they did, but it was necessary to protect Diana. Rosalee then asks what's left for the suppressant and Adalind tells her just her mother. The guys arrive with items from the trailer and tell Rosalee and Adalind what Juliette did. Nick tells Adalind they need to get her some place safe, so everyone tries to decide where the last place Juliette would look would be.

Nick and Hank take Adalind to Bud's house since his wife and kids are out of town. Nick introduces Bud and Adalind and Nick tells Bud nobody can know that she is there. Bud is then caught up on recent events with Adalind and Nick expecting a child and Nick and Juliette's breakup. Nick tells Bud not to tell Juliette anything if she contacts him and Hank tells Bud Juliette wants Adalind dead.

Juliette informs Kenneth that Kelly believes Nick is in danger and is on her way. Juliette tells him not to underestimate Kelly and he says he doesn't, and tells Juliette he doesn't underestimate her either. Juliette turns around to leave, but Kenneth tells her there is an open room for her. Juliette states that he doesn't think Adalind is coming back and Kenneth says he doesn't see why she would. He says Nick is probably taking good care of her now that he knows he's going to be a dad. Kenneth notices an ash mark on the back of Juliette's hand and asks "Been burning some bridges?" Juliette tells him it was a little payback and he says there will be a lot of that.

Nick arrives home with his gun drawn. He searches to see if Juliette is there and notices ash marks on the computer mouse.

In a swimming pool, Captain Renard is face down and unconscious. He wakes up and panics before swimming to the edge of the pool.

Nick and Hank meet Wu at the scene of Mary Ann's body and then go talk to Heidi, who found Mary Ann's body. They question her and as she starts getting emotional, she briefly woges, so Nick tells her he is a Grimm. Nick asks her if Mary Ann was Wesen also, and she tells him she was a Fuchsbau. Nick and Hank ask a couple more questions and then Wu has someone take Heidi home. The three of them go examine Mary Ann's body and see that her throat is slit. Nick then notices the wound on her stomach and says "This is more than just a cut."

Monroe, Rosalee, Renard, and Adalind watch as Catherine Schade's casket is taken out of the ground. Before they leave, Adalind goes and tells her mother what has happened since she died and says that after she gets Diana back, she is going to raise both of her children the right way.

At the precinct, Hank does a background check on Mary Ann and then Wu comes up to the detectives. He tells them that the M.E. report says that Mary Ann's uterus was skillfully removed using a sharp blade. Nick looks at the report and notices that it says the killer is likely left handed. Hank says the case is sounding familiar and Nick asks if he is thinking Jack the Ripper. Nick then does an internet search on Jack the Ripper.

Nick, Hank, and Wu go to Renard in his office to tell him their theory that they could be dealing with a Jack the Ripper copycat. Hank says they haven't tied the killer to anymore victims yet, but they're doing a five state search. They leave the office and Nick suggests the victims in the 1800's could have also been Wesen and Hank says it sounds like Jack the Ripper could have been a Grimm. Nick says he wishes they had the trailer and Hank says not everything got destroyed, so they could get lucky.

At the spice shop, Adalind says she can't cut into her mother's body, so Rosalee takes over. Rosalee cuts out Catherine's liver and gallbladder, and Monroe puts them into the cauldron. Monroe pulls Catherine's mouth open and Rosalee cuts out her tongue. Rosalee then hands Monroe a chisel and hammer to crack Catherine's ribs so they can remove them, but before he can do anything, Nick and Hank arrive. He then goes to the basement with them to search the diaries.

Nick and Hank let Monroe know they're looking for something on Jack the Ripper or someone like him.

Heidi is waiting for a client, when the killer walks up to her. He tells her he is looking for something a Kehrseite wouldn't understand and she woges. He tells her his friends call him Jack and calls her by her name. She asks if she knows him and he tells her he's been watching her. He notes she's been talking to the police and stabs her.

In the spice shop basement, Monroe finds some info about similar cases from the Luxembourg Peasant's Revolt in 1798. Based on the brutality of the killings, the Grimm who wrote the diary was curious if the killer was another Grimm, but Monroe says the rest of the page is burned off. He continues on to the next page where the diary says the Grimm confronted a soldier who was killing a Wesen prostitute and removing various organs for an unknown purpose. The Grimm cornered the soldier and he did not woge, although there was something in his eyes "as if the Devil himself had taken hold of him." The Grimm plunged his sword into the soldier, but the soldier just smiled as if death meant nothing to him. Hank asks if this means the soldier is the killer and Nick says or something was making him do the killings.

Upstairs, Rosalee and Adalind grind the last rib and Rosalee dumps the resulting powder into the cauldron. Nick, Hank, and Monroe some into the room and tell them what they found in the diaries. Nick says that according to the books, Jack the Ripper may have been around longer than people thought. Suddenly a smelly steam cloud rises out of the cauldron and Rosalee notices Adalind is about to faint. Nick grabs her and helps her get to the bed. A little while later, a skeleton forms in the liquid in the cauldron, and Adalind says all they have to do now is strain it. Nick gets a call from Wu and and he puts him on speaker. Wu tells him Heidi's body was found and the killer has the same M.O. Nick and Hank go to the scene and Rosalee suggests to Monroe that they contact Trubel, and he agrees.

Heidi's body is uncovered so Nick and Hank can have a look and Renard comes up to them to ask if they have any leads because the Mayor's office keeps calling him to asks what they're doing with the case. Nick says no leads they can sure with the press and Renard tells him to share with him. Nick and Hank tell him about what they read in the diaries and Renard agrees he isn't taking that to the press. Renard tells them that whoever is doing this is flesh and blood, so find him.

Press Release

A SERIES OF CONNECTED MURDERS LEAD EVERYONE TO THINK A COPYCAT IS ON THE LOOSE - GARCELLE BEAUVAIS AND NICO EVERS-SWINDELL GUEST STAR - A string of homicides have the press asking Captain Renard (Sasha Roiz) if a Jack the Ripper copycat has arrived in Portland. While dealing with the investigation, Nick (David Giuntoli), Hank (Russell Hornsby), Monroe (Silas Weir Mitchell) and Wu (Reggie Lee) deal with a situation they never expected. Meanwhile, Adalind (Claire Coffee) and Rosalee (Bree Turner) must work together on a last ditch attempt to fix Juliette's (Bitsie Tulloch) condition. Elsewhere, Juliette decides to help her new ally even if it means hurting those around her.

Guest stars

Nico Evers-Swindell
Garcelle Beauvais
Danny Bruno
Bud Wurstner



Select scene

Grimm - The Hexenbiest Is Here to Stay (Episode Highlight)

Grimm - The Hexenbiest Is Here to Stay (Episode Highlight)

Production Notes


  • Renard's bleeding and blackout side effects from his mother saving his life reoccur.
  • Bud meets Adalind for the first time.
  • The first female Klaustreich is seen.
  • The trailer is badly damaged, but not all of its contents have been destroyed; subsequently, the remaining items, including some of the Grimm diaries and weapons, are moved to the spice shop basement.
  • It is revealed that Lauren Castro did not succeed in her campaign to become the mayor of Portland.


  • The names of the sent and received emails on Nick and Juliette's computer are of writers and other crew members for the show.
  • The last names of the first two murder victims, McDunnah and Casey, both are of Irish Gaelic origin. "Jack" also sings an Irish folk song after he kills Henrietta.



Start a Discussion Discussions about You Don't Know Jack

  • Jack

    6 messages
    • Sean and Jack are Irish and English variations of the same root name of John are they not? Are Renard and Jack a sort of Jekyll and Hyde? ...
  • Episode 420 - "You Don't Know Jack"

    338 messages
    • (P) Macabros77 wrote: 4 days ago I made a comment about the e-mail . But it doesn't matter which  the real facts are. ...
    • LCD2YOU wrote: (P) Macabros77 wrote: 4 days ago I made a comment about the e-mail . But it doesn't matter which  the real facts are. ...
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